how can I know whether my ISP is blocking ports?

[btrcp2000]

Have been trying to revive placeshifter, mobile web, etc., access from outside the network. It disappeared when I switched ISPs, and I always just assumed it was port fprwarding issues with a new router. Finally got around to looking at it, and the only way I can get things to work is if I put the entire server in the DMZ, so at least I know I have the forwarding right. I am able to access the port fwd settings within the router (Zyxel, combo modem/router provided by Cincinnati Bell, fiber to the home 100mbps), so it's not explicitly blocked off. Also, I have been able to set it forwarding to both playon and plex, which work fine.

Cin Bell wants to send me to Premium tech support just to answer the question of whether they are blocking. The internet service has been great, but tech support is an adventure every time.

I used some online tools to determine that specific ports are open when the server is in DMZ vs closed when it's not, so I'm pretty sure it's the ISP, right?

Is there a way to find an open port if they are not blocking all? Or am I totally off base to begin with?

[will]

Originally Posted by btrcp2000

Zyxel, combo modem/router provided by Cincinnati Bell, fiber to the home 100mbps

I don't use that exact model but I do use a Zyxel USG as my router. Not sure if the are similar or not but on my router, I need to not only make sure port forwarding is setup but that also my firewall allows the service from the WAN (internet) to access an IP on my LAN. If you only allow one or the other it will be blocked.

If you can, try shutting off the firewall and see if it works. If it does then that should indicate a misconfiguration of the firewall.

[KarylFStein]

Originally Posted by btrcp2000

Have been trying to revive placeshifter, mobile web, etc., access from outside the network. It disappeared when I switched ISPs, and I always just assumed it was port fprwarding issues with a new router. Finally got around to looking at it, and the only way I can get things to work is if I put the entire server in the DMZ, so at least I know I have the forwarding right. I am able to access the port fwd settings within the router (Zyxel, combo modem/router provided by Cincinnati Bell, fiber to the home 100mbps), so it's not explicitly blocked off. Also, I have been able to set it forwarding to both playon and plex, which work fine.

Cin Bell wants to send me to Premium tech support just to answer the question of whether they are blocking. The internet service has been great, but tech support is an adventure every time.

I used some online tools to determine that specific ports are open when the server is in DMZ vs closed when it's not, so I'm pretty sure it's the ISP, right?

Is there a way to find an open port if they are not blocking all? Or am I totally off base to begin with?

If it works in the DMZ on your router but not behind it then it's not your ISP blocking anything. I imagine will is right that you need to not only port forward but add a firewall rule.

[btrcp2000]

Are we talking about the routers firewall or the server (windows)? Or both?

On the server, everything with sage in it is permitted through the firewall

On the router I had set it to "easy" which allows Wan to Lan access and also turned it off entirely, no luck.

How do I set a rule?. New one for me

[will]

Originally Posted by btrcp2000

Are we talking about the routers firewall or the server (windows)? Or both?

On the server, everything with sage in it is permitted through the firewall

On the router I had set it to "easy" which allows Wan to Lan access and also turned it off entirely, no luck.

How do I set a rule?. New one for me

I'm talking about the router firewall. If it works in the DMZ then it would not be a software firewall issue; that indicates it is a router mis-configuration.

I 'm not familiar with your model or the "easy" option. The Zyxel router I use is a business class router so I wouldn't be surprised if my configuration interface is very different than yours.

I recommend looking in the manual for instructions on configuring:

1. NAT forwarding (this is the port forwarding)
2. Firewall rules

If you have a specific network questions or a question about what ports are needed I can help you with that but I unfortunately can't help you with the actual step-by-step configuration of your device.